אֶת־יְהוָ֥ה הֶאֱמַ֖רְתָּ הַיּ֑וֹם לִהְיוֹת֩ לְךָ֨ לֵֽאלֹהִ֜ים וְלָלֶ֣כֶת בִּדְרָכָ֗יו וְלִשְׁמֹ֨ר חֻקָּ֧יו וּמִצְוֺתָ֛יו וּמִשְׁפָּטָ֖יו וְלִשְׁמֹ֥עַ בְּקֹלֽוֹ׃
네가 오늘날 여호와를 네 하나님으로 인정하고 또 그 도를 행하고 그 규례와 명령과 법도를 지키며 그 소리를 들으리라 확언하였고
Rashi on Deuteronomy
האמרה, האמירך are words for the meaning of which there is no decisive proof in Scripture. It seems to me, however, that they are expressions denoting “separation” and “selection”: “You have singled Him out from all strange gods to be unto you as God — and He on His part, has singled you out from the nations on earth to be unto Him a select people”. [As far as this meaning is concerned I have found a parallel (lit., a witness) to it where it bears the meaning “glory”, as in (Psalms 94:4): “All wrongdoers glory in themselves”].
Ramban on Deuteronomy
THOU HAST AVOUCHED THE ETERNAL THIS DAY. The meaning thereof is: “Since you have accepted the entire Torah upon yourselves with all its interpretations, details, and new promulgations, you have thus magnified G-d and exalted Him, that He alone will be your G-d; you will in no way avow another god.”
Sforno on Deuteronomy
In this respect, את ה' האמרת היום, when you accepted upon yourself to become a party to this sacred oath, which puts at risk every physical goodness on earth in the event that you desecrate this oath האמרת, by doing so you elevated the image of the Lord, Who, as a result, will be even more honoured in your eyes than before you entered into this reciprocal covenant with Him. You have thereby demonstrated that it is more important for you to do His will than to enjoy any of the transient pleasures of this life.